Using a Custom Protocol

Using a Custom Protocol

Greenplum provides protocols such as
gpfdist, http, and file for
accessing data over a network, or you can author a custom protocol. You can use the
standard data formats, TEXT and CSV, or a custom data
format with custom protocols.

You can create a custom protocol whenever the available built-in protocols do not suffice
for a particular need. For example, if you need to connect Greenplum Database
in parallel to another system directly, and stream data from one to the other without the
need to materialize the system data on disk or use an intermdiate process such as
gpfdist.

Author the send, receive, and (optionally) validator functions in C, with
a predefined API. These functions are compiled and registered with the Greenplum Database. For an example custom protocol, see Example Custom Data Access Protocol.

After writing and compiling the read and write functions into a shared
object (.so), declare a database function that points to the .so file and function
names.